1. Field of the Invention
The present invention relates to a communication apparatus for receiving a content signal, a communication apparatus for transmitting a content signal, a communication system for transmitting and receiving a content signal, and methods for the same.
2. Description of the Related Art
In recent years, along with the development of Internet, computer, mobile communication, and other technologies, it has become possible for individual users to obtain a variety of content data in accordance with need at a necessary time and at a necessary place.
In a communication system using existing Internet and mobile communications, a specific communication line established by using an integrated services digital network (ISDN), a cellular system using an up-down channel, or another communication media able to communicate bidirectionally is used for transmitting a content request signal from a terminal device of a user to a server device and for transmitting a content signal in accordance with the content request signal from the server device to the terminal device which sent the content request signal.
In this case, in an existing cellular system, the bit rate (communication capacity) at the time of transmitting a signal from a server device to a terminal device (down direction) and a bit rate at the time of transmitting a signal from the terminal device to the server device are the same. Furthermore, the time assigned for an up direction and the down direction are also the same.
However, since the amount of data of a content signal to be transmitted from the server device to the terminal device (down direction) is normally very large compared with that of a signal transmitted from the terminal device to the server device, there is a disadvantage that the communication time in the down direction always becomes longer.
Therefore, a communication system assigning a longer time for the communication of the down direction than that of the up direction within a unit time in a time division duplex (TDD) system has been proposed.
As explained above, however, although a longer time is assigned to the communication of the down direction than that of the up direction within a unit time, the bit rates themselves are same in the communication of the down direction and that of the up direction and there is a limit in shortening the communication time of the down direction.
Also, in the up direction communication, it becomes necessary to increase the transmission power of the terminal device by the amount of shortening of the time assigned for the up direction communication within the unit time, there is a limit to an assignable time for the down direction communication for a unit time, and thus the communication time for the down direction cannot be sufficiently shortened.
Also, there is a disadvantage that the load involved in changing an existing cellular system where the communication times for the up direction and down direction communications within a unit time are set to be the same so that a longer time is assigned to the down direction communication than the up-direction communication within a unit time becomes large.
An object of the present invention is to provide a communication apparatus for receiving a content signal, a communication system for transmitting a content signal, and a communication system for receiving and transmitting a content signal capable of improving the bit rate of the down direction communication by using an existing bidirectional communication system and methods of the same.
To solve the above disadvantages of the prior art and to achieve the above object, a communication apparatus according to a first aspect of the present invention comprises a communication apparatus comprising a transmitting and receiving means for transmitting and receiving a control signal to and from a first communication apparatus; a first control means for controlling the bidirectional communication between said first communication apparatus using said transmitting and receiving means; a receiving means for receiving a content signal from a second communication apparatus; and a second control means for transmitting and receiving a control signal to and from said second communication apparatus via said first communication apparatus by using said bidirectional communication controlled by said first control means and controlling the reception of said content signal by said receiving means based on results of the transmission and reception.
Furthermore, the communication apparatus according to the first aspect of the present invention specifically has transmitting and receiving means which transmits and receives said control signal to and from said first communication apparatus by using a first wireless network and has receiving means which receives said content signal from said communication apparatus by using a second wireless network.
Also, the communication apparatus according to the second aspect of the present invention provides a communication apparatus comprising a transmitting and receiving means for transmitting and receiving a control signal to and from an other communication apparatus; a first control means for controlling bidirectional communication with said other communication apparatus using said transmitting and receiving means; a transmitting means for transmitting a content signal to said other communication apparatus; and a second control means for transmitting and receiving said control signal to and from said other communication apparatus by using said bidirectional communication controlled by said first control means and controlling transmission of said content signal by said transmitting means based on results of said transmission and reception.
Also, the communication system of the present invention is a communication system for performing bidirectional communication between a first communication apparatus and a second communication apparatus, wherein said first communication apparatus comprises a first transmitting and receiving means for transmitting and receiving a control signal with said second communication apparatus; a first control means for controlling bidirectional communication with said second communication apparatus using said first transmitting and receiving means; a transmitting means for transmitting a content signal to said second communication apparatus; and a second control means for transmitting and receiving said control signal to and from said second communication signal by using said bidirectional communication controlled by said first communication means and controlling transmission of said content signal by said first transmitting means based on results of the transmission and reception; and aid second communication apparatus comprises a second transmitting and receiving means for transmitting and receiving a control signal with said first communication apparatus; a third control means for controlling bidirectional communication with said second communication apparatus using said second transmitting and receiving means; a receiving means for receiving a content signal from said second communication apparatus; and a fourth control means for transmitting and receiving said control signal to and from said second communication signal by using said bidirectional communication controlled by said third communication means and controlling reception of said content signal by said receiving means based on results of the transmission and reception.
Also, the communication method of the present invention is a communication method for performing bidirectional communication between a first communication apparatus and a second communication apparatus including the steps of performing bidirectional communication between said first communication apparatus and said second communication apparatus via a first wireless network; transmitting a content signal from said first communication apparatus to said second communication apparatus via a second wireless network; and performing mobile management, call control, and wireless management necessary for said bidirectional communication using said first wireless network in an independent form from mobile management, call control, and wireless management necessary for receiving said content signal using said second wireless network.